5 speed manual trans problems

I have a 96 chev 1500 and the 5 speed trans is noisey.It shifts and works good but when it gets warmed it is noisey.The noise is clattering clicking noise when you take your foot off gas when driving.It seems to quit when engine is pulling.Is this trans hard to rebuild?What years trans will interchange with it? It is a 4.3 mg5.Also do anyone know where to buy one reasonable price? thanks phil:banghead:

Have you changed the oil in the trans lately (GM Synchromesh oil)?